(description borrowed from https://blog.actionpact.com/2015/04/22/brain-games-the-copycat-syndrome/)
A recent episode of “Brain Games” featured a social experiment on human behavior. They staged a waiting room where everyone (except one person, the subject) was instructed to stand up every time they heard a beeping noise.
After only a few beeps, the subject began standing up with the rest. She was not rewarded or instructed to do so, but she did it anyway. Slowly all the other participants left the waiting room, leaving only the subject. She kept standing at the beep. Then as new subjects entered the waiting area, all but one person mimicked her behavior and stood at each beep.